(declare-fun a () String)
(declare-fun b () String)
(assert (not (str.in_re (str.++ a "AB") (re.* (re.++ (str.to_re "A") (str.to_re b))))))
(assert (str.in_re (str.++ a b) (re.+ (str.to_re "BB"))))
(assert (str.in_re a (re.* (str.to_re "A"))))
(check-sat)
(assert (not (str.in_re (str.++ a "AB") (re.* (re.++ (str.to_re "A") (str.to_re b))))))
(assert (str.in_re (str.++ a b) (re.+ (str.to_re "BB"))))
(assert (str.in_re a (re.* (str.to_re "A"))))
(check-sat)
